This section illustrates useful background information without admission of any technique described herein representative of the state of the art.
Home routers are commonly used for internet access at home and in corporations. Home routers conveniently share a single internet connection for a number of devices attached to the router so that many devices could use same internet connection concurrently. In addition the home routers often support routing between the attached devices, i.e. devices on the ingress side of the router (also called as an intranet). With a router, all attached devices share one internet address (IP address) for the Internet outside the local network that is formed by the router with the attached devices.
The universality of the Internet is reflected by home routers in particular. They can be used to share an internet connection with the attached devices quite independently of the physical implementation of the internet connection that may be a cable television, ADSL, satellite data, cellular, optical fiber, modulation on power lines, laser links, or anything at all, as long as the physical connection is capable of transferring data in a form supported by the home router. Typically, that form supported by the routers is internet protocol (IP), in which data packets are transferred typically using TCP or UDP communication protocols, for example. Thanks to the Internet standardization, physical link implementation or layer 1 of the OSI model is unimportant for the higher levels such as layer 2 on which the Internet protocol and flow control (such as the TCP and UDP) operate. Applications that use Internet connectivity operate on yet higher level of the OSI model. This system greatly simplifies design and implementation of complex communications systems, as one layer can call standardized services of a lower protocol layer by use of standardized primitives or interlayer messages.
Some home routers are equipped with modem circuitry. A modem is a device that forms a physical link with an Internet service provider. In such a case, the number of separate units is reduced from two to one for connecting the attached devices to the Internet. Such integration also removes the need for suitable sockets and interconnecting cable, such as a LAN cord with two male RJ-45 ends as well, and requires only one mains socket instead of two. Moreover, the settings of both units can be controlled through one built-in web server with which a user can set up both modem and router settings and thus one password suffices for administration. Beside these integration aspects, both the modem side and the router side operate exactly as if they were provided by separate boxes.
Often, home routers are also configured to operate as firewalls. A firewall typically keeps track of packets sent from the ingress side to the egress or wide area network side and only accepts reply packets that not only are addressed to the Internet address (egress address) with which the home router appears on the egress side, but that also identifies themselves as such reply packets. This is also referred to as stateful packet inspection (SPI) wherein the firewall that keeps track of the state of network connections and allows only such incoming packets that match a known active connection while simply deleting others without any acknowledgement to their sender. That way malicious attackers cannot find open ports the firewall prevents response to so-called ping packets on all ports because these packets originate from the egress side without any connection to which they would relate to. By combining all of a firewall, modem and router it is possible to control all three different functionalities with a single administrator password using a browser in a local device, for example. Moreover, a relatively safe network can be simply set up by plugging in and powering one small box between the Internet service provider and the connected devices.
It is now desired to enhance capabilities of modem enabled routers or to at least provide a new technical alternative for existing modern enabled routers.